The choice of the most efficacious conservative or surgical treatment for patients with overactive bladder (OAB) remains challenging. The aim of this systematic review was to assess the efficacy and adverse events of conservative or surgical treatments for overactive bladder, namely botulinum toxin (BoNTA), sacral neuromodulation (SNM), transcutaneous or percutaneous tibial nerve stimulation (TTNS, PTNS). We focused on the individual symptoms of the OAB syndrome to provide an advice for the best treatment for each individual symptom.

A comprehensive literature search was done in PubMed, EMBASE and Cochrane Central Register of Controlled Trials from inception to December 1, 2021. We restricted language to English, Italian and Dutch. We included only randomized controlled trials (RCTs) related to idiopathic overactive bladder with at least 12 weeks of treatment. The risk of bias was assessed Revised Cochrane Risk of Bias Assessment Tool.

Sixteen articles met our inclusion criteria, referring to 13 different RCTs.  Overall, 13, 12, 8 and 7 RCTs assessed the effects on nocturia, frequency, incontinence, and urgency episodes, respectively. Females represented the majority of the study population.  Results are depicted in table 1.

BoNTA resulted superior to placebo in reducing all the symptomatology. Contrasting results were reported for PTNS vs TTNS and BoNTA and neuromodulation. 
For urinary incontinence the injection of BoNTA 200 U generated a greater reduction of the incontinence episodes compared to SNM. However, because of the small difference in reduction (0.52, 95% CI, -0.04 to 1.09, p = .07) SNM still remains a valid choice for predominant incontinence.
Nocturia was the most investigated symptom. Different units of BoNTA were used with good results. Additionally, all the conservative alternatives seemed to cause an improvement of nocturia.
For urgency and frequency episodes BoNTA seems the most effective treatment, since reported data on PTNS were contrasting. However, when comparing Sham and PTNS, a greater reduction of urgency episodes was seen for PTNS.
As the clinical trials used different questionnaires, we could not directly compare the efficacy of the treatments, all of which provided an improvement in QoL and patient’s satisfaction. Uncomplicated urinary tract infection was the most frequently reported adverse event. However, the used definitions for UTI differed between studies.  Discontinuation of treatment due to adverse events was infrequent.

To our knowledge, this study represents the first attempt to comprehensively summarize conservative and surgical treatments for overactive bladder. After systematic review of the literature, no clear superiority of a single option could be demonstrated. However, due to the numerosity of the evidence supporting BoNTA, this might be considered the first invasive option given its efficacy and good tolerability profile. Future research should focus on comparison of other treatments options for OAB which are greatly underrepresented in current literature